Traveling grate stoker



Sept. 3, 1957 RI c. RIVERS 2,804,334

TRAVELING ems STOKER Filed March 19, 1954 2 Sheets-Sheet 1 lllllLq l BY%Y Sept. 3, 1957 R. c; RIVERS TRAVELING GRATE STOKER Filed March 19,1954 2 Sheets-sheet 2 INVENTOR Passe-u. 6. RIVERS A ORNEY TRAVELINGGRATE STOKER Russell C. Rivers, Boylston, Mass., assignor to RileyStoker Corporation, Worcester, Mass, a corporation of MassachusettsApplication March 19, 1954, Serial No. 417,380

2 Claims. (Cl. 110-40) This invention relates to traveling grate stokersand more particularly to a grate for use with a spreader stoker in asteam generating apparatus.

In the firing of coal in a steam generating apparatus, it is commonpractice to project the coal into the furnace by means of a spreaderstoker so that the coal falls on the upper surface of an elongatedtraveling grate. The coal burns on the grate surface and the ash iscarried by movement of the grate to one extremity of the grate where theash falls over the end into an ashpit. Many difficulties have beenexperienced with traveling grates of this type in the past. Inpreviously known constructions, the bars were easily burned and the barssuffered from the disability that ash sifts through very easily.Furthermore, the bearings which support the moving elements in theseprior art grates are forced to carry extremely heavy loads underdiflicult conditions. The replacement of damaged or burned-out bars alsohas required the complete shut-down of the furnace and involved atime-consuming operation. These and other difficulties which have beenexperienced with previously-known grates are obviated by the presentinvention in a novel manner.

It is therefore an outstanding object of the present invention toprovide a traveling grate construction in which the bars may be quicklyremoved from any position without disturbing the rest of the bars andwithout disturbing the fuel bed.

It is another object of the present invention to provide a travelinggrate having bars in the construction of which no machining is required,so that the alloy used may be very hard.

It is a still further object of the present invention to provide atraveling grate construction in which there is no necessity for reversedbending of the chain so that it is possible to use a tight-fittinginterlocking bar construction, thus offering less leakage and lessburning of intricate exposed bar construction.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the features hereinafter fully described andparticularly pointed out in the claims, the following description andannexed drawings setting forth in detail certain illustrativeembodiments of the invention, these being indicative, however, of but afew of the various ways in which the principle of the invention may beemployed.

In said annexed drawings:

Figure 1 is a Vertical sectional view of a traveling grate constructedunder the philosophy of the present invention,

Figure 2 is an enlarged view of a portion of the apparatus shown inFigure l, with portions broken away for clarity of presentation.

Figure 3 is a vertical sectional view of the apparatus of the inventiontaken on the line IIIIII of Figure 2, and

Figure 4 is a perspective view of an element of the invention.

Like reference characters denote similar parts in the several figures ofthe drawings.

States Patent Patented Sept. 3, 1957 Referring first to Figure 1 whereinis best shown the general features of the invention, the gratedesignated generally by the reference numeral 10, is shown in use in thelower portion of a furnace 11. The furnace 11 comprises a front wall 12and a rear wall 13 defining a combustion chamber 14. The front wall 12is offset to overlie one end of the grate 10. It is supported on a beam15 and serves as one wall of an ashpit 16 underlying the end of thegrate. The wall 11 is provided with waterwall tubes 17 extendingupwardly from a header 18 and a spreader stoker 19 is mounted on thewall 11 some distance above the grate 10 with a suitable aperture in thewall provided for the projection of fuel therethrough by the stocker.The rear wall 13 is mounted on a beam 20 and is provided with a seal 21which contacts the grate. A header 18' provides for flow to water walltubes 17'. I

The grate 10 consists in general of a number of bars linked together toform an endless chain. This chain is mounted on and supported by asprocket 23 underlying the rear wall 13 and a sprocket 24 underlying thefront wall 11. The sprocket 23 is keyed to and mounted on a journalshaft 25 which is in turn mounted in suitable bearings 26 while thesprocket 24 is mounted on a shaft 27 which is carried by suitablebearings 28. The shaft 27 is suitably driven by conventional means, notshown. The upper run of the grate is held in a substantially levelposition by supporting means including beams 29 which extend from oneside to another of the furnace. A rail 39 underlies the grate from itsposition under the wall 12 to a position substantially rearward of thecentral position of the furnace and this rail is supported by beams 31extending transversely of the furnace. A shoe 32 is pivotally mounted tothe forward end of the rail 30 and has a curved upper end which pressesagainst the forward end of the grate.

In Figure 2, which is an enlarged view of the forward end of the grate,it can be seen that the grate is made up of a series of bars 33, whichare pivotally attached at their forward ends to a linked chain 34 whichis in turn driven by the sprocket 24. The upper run of the series ofbars 33 rests on a horizontal rail 35 which in turn rests on the beams29, as is evident in Figure 1. It is to be observed that the bars 33interlock with one another particularly in their horizontal runs to forma substantially solid surface for the carrying and burning of fuel. Thecurved upper portion of the shoe 32 embraces these bars around theforward end of the grate and prevents them from opening up as they wouldotherwise do because of the fact that they are pivoted at one end only.The lower end of the shoe-32 is provided with a substantial weight whichbiases it toward a vertical position. The shoe is attached to theforward end of the rail 30 by means of a pin passing through a suitablebore in a block which is adjustably fastened to the forward end of therail 30.

The details of construction of the bars 33 are particularly well shownin Figure 2. The upper surface of each of the bars is slightly curvedlongitudinally of the furnace and is provided with a number of air holes41. The forward end is provided with a curved skirt 42 which is providedwith slots 43 and 44 for a purpose to be explained more fullyhereinafter. The rearward end of each of the bars 33 is provided with adownwardly directed curved nose 45 which rides along the surface of theskirt 42 of the immediate adjacent rearward bar. The link belt 34 ismade up of individual links 46 joined together by transverse pins 47.Each bar 33 is provided with vertical transverse webs 48. A lockingmember 49 is associated with the pins 47 and the webs 48 to lock thebars 33 in place on the link chain 34.

In Figures 3 and 4 is shown the manner in which the locking member 49cooperates with the other members,

To begin with it should be noted that each bar 33 is compartmentized byvertical longitudinal walls such as the end wall 50 and an intermediatewall 51 defining a compartment 52. The vertical web 48 mentionedhere'inb'efore extends into the compartment 52 from the wall 51 and asimilar vertical web 53 extends toward it from the end wall 50. The pin47 extends transversely of the compartment 52 and is limited in itsendwise movement by the intermediate wall 51 and by a lug 54 extendinginto the compartment from the end wall 50.

A roller 55 is mounted on the central portion of the pin 47 and isengaged by the teeth of the sprocket 24. At each end of the roller 55and joined by the pin 47 are links 46 of the link chain 34. Mounted onthe outer end of the pin 47 is a similar locking member 56 which engagesthe web 53. The locking members 4 and 56 are very similar except thatone is right hand and the other is left hand for engagement with rightand left webs in the manner shown. Figure 6 shows a left hand lockingmember 56 which is representative of the rest of the locking members.The locking member 56 is of a generally block-like configurationprovided with a transverse bore 57 through which passes the pin 47. Itis also provided with a slot 58 in which the web 53 resides. In theupper portion of the block and extending longitudinally thereof is asmall bore 59 through which may pass a cotter pin 60 as is evident inFigure 2. The locking member 56 is provided with a rounded portion'filat the end adjacent the bore 57. This is done to provide a sufiicientbulk of metal around the bore 57. A recess 62 is provided adjacent thebore 59 in order' to provide for the head of the cotter pin 60. Itshould be noted that each slot 44 in the skirt 42 of each bar 33 isaligned with a cotter pin 69, while each slot 43 is aligned with a linkchain 34. It also should be noted, as is evident in Figure 3, that anotch 63 is provided in the vertical edge of the web 48, while a similarnotch 64 is provided in the vertical edge of the web 53.

The operation of the invention will now be evident in view of the abovedescription. The shaft 27 is driven so that it rotates in its bearings28 carrying with it the sprocket 24. The teeth of the sprocket 24 engagethe rollers 55 thus carrying the pins 47. The movement of the pins 47carries the link chains 34 and the bars 33, the latter being driventhrough the medium of the locking members 49 and 56. The rollers rest onthe rail 35 sup ported by the beams 29 along the upper run of the belt.This provides for a smooth horizontal upper grate run. The spreaderstoker 19 is, of course, operating and projecting fuel upon the upperrun of the grate in the usual manner. The fuel is moved forwardly in thefurnace, that is to say, toward the front wall. 12 and the ash isdeposited in the ashpit 16. As the bars 33 pass over the forward end ofthe grate, they are free to rotate about their pins 47, the rearwardend-of each bar being free. However, the shoe 32 presses against the.bars and holds them in a position generally tangential to the sprocket24. The shoe is pressed against the bars under the lever action providedby the weight of its lower end. If, however, a piece of foreign mattercomes in contact with the shoe or jams a bar into open position, theshoe is free to swing about its pivot pin and move out of the way. Aseach bar 33 proceeds further around the forward end of the grate, itleaves the shoe 32 and a time later comes in contact with the rail 3tFor a short space, the bar is free to rotate outwardly before it isagain forced into alignment with the other bars. The bars have nowmovedinto the lower run of the grate and bars in this position are supportedby the rail 30, in a position considerably above that which they wouldoccupy if they were hanging freely. That is to say, the bars are notpermitted to hang by their pins 47 in a downward, open position.However, after each bar leaves the rail 30 at the rearward end, itswings about its pin 47 into the open, pendent position shown in Figure1; This permits any ash that may have I the bar which is to be removed.This exposes the slot 44 and permits the operator to obtain access tothe cotter pin 60. It is only necessary then to remove all cotter pins60 and the bar may be removed from the locking members 49 and 56. Inmost cases it is not necessary to stop the grate. Access doors may beprovided adjacent the lower run of the grate in order to permit theremoval and replacement of a grate in such a manner. To place a newgrate in position, it is only necessary to drop the new bar in positionwith the webs 48 and 53 sliding into the slots 58 in the lockingmembers. Then cotter pins 69 are inserted through bores 59 so that theintermediate portion of the cotter pin resides in the notches 63 and 64.The bar is then locked in place. This same action serves to lock the pin47 against lengthwise movement; that is to say, the pin47 may only beremoved from the locking members, the link chains, and the rollers aftera bar has been removed.

The slots 43 in the skirts 42 of the bars 33 are provided to permit thebars to swing freely about their pins 47. In the pendent position shownin Figure l, the link chains reside in these slots 43. Otherwise, theskirts 42 would strike the link chains 46 and prevent rotation of thebars.

Other modes of applying the principle of the invention may be employed,change being made as regards the details illustrated, provided thefeatures stated in the following claims or the equivalent of such beemployed.

I therefore particularly point out and distinctly claim as my invention:

1. A traveling grate comprising a plurality of endless link chains inspaced parallel longitudinal relationship, a series of grate bars, eachextending transversely between two chains, each grate bar pivotallyconnected at each end to one of its chains and having its opposite edgeengaging the surface of the immediately-longitudinally-adjacent bar inclosed slidable contact, short pivot pins joining adjacent links of eachchain and extending transversely from each side for a short distance,two locking members mounted one at each end of said pins joining eachpin with the end portion of a grate bar, each locking member mountingcomprising a bore by which it is pivotally-mounted on its pin, the gratebar having two longitudinal flanges which extend across the ends of thepin and prevent it from leaving the chain and locking members,transverse flanges extending downwardly from the grate bar adjacent eachlongitudinal flange, a slot formed in each locking member in which atransverse flange resides, said grate bar being mounted over said p nwith said latter flange mounted in said slot, and means selectivelyretaining each transverse flange in the slot of its locking member.

2. A traveling grate comprising a plurality of endless link chains inspaced parallel longitudinal relationship, a series of grate bars, eachextending transversely between two chains, each grate bar pivotallyconnected at each end to one of its chains and having its opposite edgeengaging the surface of the immediately-longitudinally-adjacent bar inclosed slidable contact, short pivot pins joining adjacent links of eachchain and extending transversely from each side for a short distance,two locking members mounted one at each end of said pins joining eachpin with 70 the end portion of a grate bar, each locking member verseflanges extending downwardly from the grate bar adjacent eachlongitudinal flange, a slot formed in each locking member in which atransverse flange resides, said grate bar being mounted over said pinwith said latter flange mounted in said slot, a notch in each transverseflange being aligned with a second bore in its respective lockingmember, and a cotter pin passing through the second bore and residing inthe said notch.

References Cited in the file of this patent UNITED STATES PATENTS575,092 Allen et al. Ian. 12, 1897 6 Van Brunt May 22, 1928 Holt Aug.28, 1934 Lem'aire Sept. 7, 1937 Beers Sept. 1, 1942 Beers Aug. 22, 1944Beers Nov. 28, 1944 Sparks July 19, 1949 Bennett et a1. Apr. 24, 1951

